Since many nerves were damaged due to an operation and it didn't work too well before the operation, there is not much you could do unfortunately. But there are a few things you could try. First of all, no porn. For at least 6 months. Good feelings, not an orgasm should be the goal. Some manage with very light electrostimulation. But that should be last resort since nerve damage or sensitivity downregulation can occure. But the best tip would be an appointment with an urologist, since they are really the best experts in this case.